Oil paintings are complex, multi-layered systems that are prone to chemical degradation. While it is increasingly recognised that water plays an important role in these degradation reactions, little is known about moisture concentrations in oil paint systems and their temporal variation in response to fluctuating ambient air humidity. This knowledge is necessary to further preventive conservation, specifically to establish optimal environmental conditions to safeguard works of art for future generations. We developed a transient one-dimensional moisture transport model based on Fickian diffusion enabling the integration of experimentally recorded relative humidity data. Moisture sorption and transport data for painting materials have been reviewed from literature showing that each component of a painting has rather distinct properties. Including the properties of the individual layers enabled predicting the behaviour of a multi-layered painting system. A sensitivity study indicated that the response of a multilayer is determined by the combination of diffusion coefficients, isotherm shapes, maximum water contents, layer thicknesses, period of RH fluctuation and stacking order of the layers. Finally, the model was employed to investigate a case study of 18^th-century painted wall hangings in a historic house to illustrate the insights that can be gained from this approach and the types of conservation-related questions that can be answered.

@en

The Martenahuis in Franeker contains a special room whose walls and ceiling are decorated with vast paintings on canvas. Such fully painted rooms were very popular in the northern Dutch provinces from the last quarter of the seventeenth century and were called 'painted rooms' or 'rooms in the round'. Owing to later additions and alterations, the painted room in the Martenahuis presents a disjointed picture today. The room's original appearance has been reconstructed with the help of material-technical, art-historical and archival research. It transpires that all the elements of the room were meticulously coordinated with one another, which provides insight into the intentions of the client and the artists involved. The now white-painted flat wooden architectural elements were originally painted with a reddish-brown trompe l'oeil representation which, together with the paintings inserted into them, created the illusion of a richly decorated classical pavilion overlooking Arcadian landscapes. Technical research revealed - in contrast to what the literature had previously suggested - that all the landscape hangings, as well as the central ceiling piece and the eight original wainscot paintings, were part of a single series made especially for this room. Archival research has shown that the room came into being in or shortly after 1701, follow ing the departure in Aug ust 1701 of the young Fr isian stadholder Johan Willem Friso (1687-1711), who had stayed there while studying at Franeker University. The construction of the room was part of a large-scale renovation commissioned by the wea lt hy regent Suffridus Wester-huis (1668-1731), who had acquired the building in 1694. Various prints by the French architect Daniel Marot (1661-1752) served as inspiration for the room's design. Those designs were all published before 1703. There are no elements dating back to Marot's inventions from or after 1703, such as those included in his collected edition of 1712, whereas this is regularly the case in Frisian buildings built after 1703. As such, the painted room in the Martenahuis is one of the earliest examples of the Marot style in an upper middle-class mansion. The ambitious Suffridus Westerhuis presented himself as a modern and wealthy man of standing by having his house renovated in line w ith the latest architectural and interior design ideas. What's more, the painted room he created directly mirrored Marot's designs for Willem iii (1650-1702) and his inner circle. One of the artists Westerhuis chose to do the landscape paintings in his reception room was the painter Jan van Bunnik (1654-1733), who created decorations for the palaces of the stadholder-king and for the country houses of his entourage. In seeking to align himself with the Republic's highest echelons, Westerhuis was presenting himself as an administrator of high standing. Westerhuis took a keen interest in gardening and the study of nature, a highly appropriate pastime for a prominent figure at that time. As such, his choice of landscape hangings as wall decoration was quite apt. The contemplation of such landscapes was viewed at the time as a form of relaxation after onerous adminis-trative duties. Architecture, paintings and client turn out to be inextricably linked in the Martenahuis room - a connection which, after having been concealed for centuries, has been brought to light by this recent research project.@en

This case study explores the original significance and contexts of a series of political allegories painted by Theodoor van Thulden (1606-1669) for the 's-Hertogenbosch (Bois-le-Duc) Town Hall. In considering their commission history, current attributions, their relevant historical and political contexts and their initial placement in the town hall, we aim to reconstruct the paintings' function as a decoration program between their installation in the late 1640s and their relocation following a substantial renovation of the building in the early 1670s. The article concludes with a reflection on the changing nature of the town hall's interior and its impact on the interpretation and appreciation of Van Thulden's paintings in the present.@en